WINETECH Technical Yearbook 2020

Site: Nuwerus Soil description: Clay, wet in winter Sowing date: Mid-June 2019 The mixture of forage rye and vetch produced average biomass on this soil. The white mustard and forage radish mixture produced a higher biomass compared to the other mixtures. The forage barley performed better than the forage rye and produced a medium to high biomass. During the winter months, this soil has the tendency to become waterlogged, therefore a cover crop with a better tolerance for wet soil conditions, such as faba bean, would be expected to do well and will be considered for the following trial. The mixture of medics and clover, which was intended for application on the grapevine row ( bankie ), performed well despite the somewhat inadequate seeding rate due to its establishment in the work row. The ability of medics, an annual regenerating sward, to re-establish on its own is dependent on various conditions, such as water availability, soil chemical and physical conditions, and the timing of chemical termination (if required). It is recommended that it be allowed to set seed before termination (if required) and that it be sown for two to three consecutive years on the grapevine row before allowing it to re-establish itself.

Approximate seed cost R/ha

Recommended sowing rate kg/ha

Performance

Treatment

Forage rye + vetch White mustard + forage radish

25 + 6

Average

650

Swartland Site: Vlakkenheuwel, Hermon Soil description: Well-weathered shale Sowing date: Mid-May 2019 All the mixtures performed well at this site. The forage rye in the forage rye and vetch mixture flourished and outperformed all the other cereals and species at this site. The white mustard produced very good stands with and without oats. The mixture of forage barley, forage peas and radish, which offers a good balance of biomass production, nitrogen fixation and bio tillage, produced good biomass and suppressed weeds. The mixture of oats, radish, stooling rye and vetch provided a dense stand with substantial biomass. The mixture of triticale and lupines also performed excellently. The phacelia produced moderate amount of biomass which was comparable to the phacelia growth at other sites in 2019. Although the medics and clover cover was recommended for application on the grapevine row, it grew extremely well in the work row at this site. It is recommended that medics be sown on the grapevine row to provide a good ground cover that is not expected to grow into the grapevine canopy.

4 + 2

Very good

445

Forage barley

50

Good/very good

450 615

Triticale + vetch Medics (on the bankie )

60 + 6

Good

5

Very good

495

Medics (left) and white mustard with radish (right) in the work row at Nuwerus, Rawsonville.

WINETECH TECHNICAL YEARBOOK 2020 131